scholarly journals BC Cassiopeiae: First detection of IW Andromedae-type phenomenon among post-eruption novae

2020 ◽  
Vol 72 (6) ◽  
Author(s):  
Taichi Kato ◽  
Naoto Kojiguchi
Keyword(s):  
Mass Transfer ◽  
White Dwarf ◽  
Transfer Rate ◽  
White Dwarfs ◽  
Mass Transfer Rate ◽  
Cataclysmic Variables ◽  
High Mass ◽  
Average Mass ◽  
Classical Nova ◽  
Decline Rate

Abstract IW And-type dwarf novae are a recently recognized group of cataclysmic variables which are characterized by a sequence of brightening from a standstill-like phase with damping oscillations often followed by a deep dip. We found that the supposed classical nova BC Cas which erupted in 1929 experienced a state of an IW And-type dwarf nova in 2018, 89 yr after the eruption. This finding suggests that a high mass-transfer rate following the nova eruption is associated with the IW And-type phenomenon. The mass of the white dwarf inferred from the decline rate of the nova is considerably higher than the average mass of the white dwarfs in cataclysmic variables, and these massive white dwarfs may be responsible for the manifestation of the IW And-type phenomenon.

scholarly journals SWSex Stars, Old Novae, and the Evolution of Cataclysmic Variables

2015 ◽  
Vol 2 (1) ◽  
pp. 188-191 ◽  
Author(s):  
L. Schmidtobreick ◽  
C. Tappert
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Cataclysmic Variables ◽  
High Mass ◽  
Period Range ◽  
Transfer Rates ◽  
Low Mass ◽  
Orbital Periods ◽  
Nova Outburst

The population of cataclysmic variables with orbital periods right above the period gap are dominated by systems with extremely high mass transfer rates, the so-called SW Sextantis stars. On the other hand, some old novae in this period range which are expected to show high mass transfer rate instead show photometric and/or spectroscopic resemblance to low mass transfer systems like dwarf novae. We discuss them as candidates for so-called hibernating systems, CVs that changed their mass transfer behaviour due to a previously experienced nova outburst. This paper is designed to provide input for further research and discussion as the results as such are still very preliminary.

scholarly journals The Effect of the Nova Explosion on the Evolution of Cataclysmic Variables

1997 ◽  
Vol 163 ◽  
pp. 771-772
Author(s):  
T. Naylor ◽  
M.W. Somers
Keyword(s):  
Mass Transfer ◽  
White Dwarf ◽  
White Dwarfs ◽  
Cataclysmic Variables ◽  
Accretion Disc ◽  
Surface Layers ◽  
Secondary Star ◽  
Classical Nova ◽  
Nova Outbursts

Classical nova outbursts are thermonuclear explosions on the surfaces of the white dwarfs in cataclysmic variables. The explosion heats the surface layers of the white dwarf, which are expected to cool on a timescale of a hundred years. The hot white dwarf should have two obvious effects on the system.(1)It will heat the surface of the accretion disc and secondary star, increasing the overall luminosity of the system.(2)By irradiating the surface of the secondary star it may bloat it and drive more mass transfer, thus again increasing the overall luminosity.

scholarly journals Classical Novae in the Context of the Evolution of Cataclysmic Binaries

1990 ◽  
Vol 122 ◽  
pp. 313-324
Author(s):  
Hans Ritter
Keyword(s):  
Mass Transfer ◽  
White Dwarf ◽  
White Dwarfs ◽  
Mass Range ◽  
High Mass ◽  
Transfer Rates ◽  
Classical Novae ◽  
Secular Evolution ◽  
Cataclysmic Binaries ◽  
Nova Outbursts

AbstractIn this paper we explore to what extent the TNR model of nova outbursts and our current concepts of the formation and secular evolution of cataclysmic binaries are compatible. Specifically we address the following questions: 1) whether observational selection can explain the high white dwarf masses attributed to novae, 2) whether novae on white dwarfs in the mass range 0.6M⊙ ≲ M ≲ 0.9M⊙ can occur and how much they could contribute to the observed nova frequency, and 3) whether the high mass transfer rates imposed on the white dwarf in systems above the period gap can be accommodated by the TNR model of nova outbursts.

scholarly journals Optical Low States of the Supersoft X-Ray Source RXJ0513.9–6951

1997 ◽  
Vol 163 ◽  
pp. 787-787
Author(s):  
K. Reinsch ◽  
A. van Teeseling ◽  
K. Beuermann ◽  
T.M.C. Abbott
Keyword(s):  
Mass Transfer ◽  
White Dwarf ◽  
Mass Transfer Rate ◽  
Central Star ◽  
High Mass ◽  
X Ray ◽  
Total Luminosity ◽  
Nuclear Burning ◽  
Sudden Decrease ◽  
Optical Flux

The transient luminous soft X-ray source RXJ0513.9–6951 (Schaeidt et al., 1993, A&A 270, L9) is a high-mass-transfer binary system (Cowley et al., 1993, ApJ 418, L63; Pakull et al., 1993, A&A 278, L39) with a probable orbital period of 0.76 days (Crampton et al., 1996, ApJ 456, 320). Here, we summarize the results of a quasi-simultaneous optical and X-ray monitoring (see Fig. 1). The sudden decrease of the optical flux, the accompanying reddening, and the turn-on in the soft X-ray band can be quantitatively described by variations in the irradiation of the accretion disk by the hot central star (Reinsch et al., 1996, A&A 309, L11). In this simple model, we consider a white dwarf with nuclear burning of accreted matter (van den Heuvel et al., 1992, A&A 262, 97), surrounded by a flat standard disk. In the optical high state, accretion at near-Eddington rate occurs and the white dwarf photospheric radius must be considerably expanded causing an enhanced illumination of the disk and the secondary. In the optical low state, the photosphere shrinks in response to a temporarily slightly reduced mass-transfer rate. At the same time, the effective temperature increases, and the soft X-ray flux becomes detectable with ROSAT. This model does not depend on the particular cause for the drop in the accretion rate and can describe the optical/ X-ray variability with the total luminosity changing by less than 20 %.

scholarly journals Critical Mass for Merging in Double White Dwarfs

1989 ◽  
Vol 114 ◽  
pp. 450-453
Author(s):  
Izumi Hachisu ◽  
Mariko Kato
Keyword(s):  
Mass Transfer ◽  
Gravitational Radiation ◽  
White Dwarf ◽  
Binary Stars ◽  
White Dwarfs ◽  
Radiation Effect ◽  
Critical Mass ◽  
Mass Transfer Rate ◽  
Roche Lobe ◽  
Common Envelope

We examine whether or not double white dwarfs are ultimately merging into one body. It has been argued that such a double white dwarf system forms from some intermediate-mass binary stars and will merge due to the gravitational radiation which decreases the separation of binary. After filling the inner critical Roche lobe, the less massive component begins to transfer its mass to the more massive one. When the mass transfer rate exceeds a some critical value, a common envelope is formed. If the common envelope is hydrostatic, the mass transfer is tuned up to be a some value which depends only on the white dwarf mass, radius, and the Roche lobe size. The mass transfer from the less massive to the more massive components leads the separation to increase. On the other hand, the gravitational radiation effect reduces the separation. Which effect wins determines the fate of double white dwarfs, that is, whether merging or not merging. Since the formula of the gravitational radiation effect is well known, we have studied the mass accretion rate in common envelope phase of double white dwarfs assuming the Roche lobe size is as small as 0.03 R⊙ or 0.1 R⊙.

scholarly journals Minimum Orbital Period of Cataclysmic Variables

1979 ◽  
Vol 53 ◽  
pp. 504-504
Author(s):  
B. Paczynski ◽  
W. Krzeminski
Keyword(s):  
Mass Transfer ◽  
Angular Momentum ◽  
Orbital Period ◽  
Time Scale ◽  
Transfer Rate ◽  
Main Sequence ◽  
Mass Transfer Rate ◽  
Cataclysmic Variables ◽  
Transfer Rates ◽  
Angular Momentum Loss

The shortest known orbital period of a cataclysmic binary with a hydrogen dwarf secondary filling its Roche lobe is about 80 minutes. Theoretically the shortest possible orbital period for such a system is less than 60 minutes. We tried to explain why the periods shorter than 80 minutes are not observed. We estimated the time scale of angular momentum loss of a cataclysmic binary and the resulting mass transfer rate. The minimum orbital period for a given Ṁ is obtained during the transition of the secondary from the Main Sequence onto the Degenerate Dwarf Sequence. Pmin ∝ Ṁ½ Therefore, only those systems can reach low P for which Ṁ is small. This explains why among the shortest period cataclysmic variables there are no novae: presumably their mass transfer rates are too large. It also indicates that “polars” (AM Her-type stars) and SU UMa-type stars should have low Ṁ.

scholarly journals MASS TRANSFER CORRELATION FOR THE REMOVAL OF COPPER IONS FROM WASTEWATER

2010 ◽  
Vol 9 (1-2) ◽  
pp. 63
Author(s):  
N. M. S. Kaminari ◽  
M. J. J. S. Ponte ◽  
H. A. Ponte
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Copper Ions ◽  
Mass Transfer Rate ◽  
Reynolds Numbers ◽  
Electrochemical Reactor ◽  
High Mass ◽  
Ore Processing ◽  
Lead Nickel ◽  
Copper Lead

One of the biggest problems with ore processing in extractive metallurgical industries is the high toxicity of the heavy metals waste content (e.g., copper, lead, nickel and chrome). This work investigates the copper (II) íons removal from aqueous solutions in concentrations up to 1000 ppm. Therefore, a fluidized bed electrolytic reactor was used with flow-by configuration considered as a hopeful method due to the large specific surface area and the high mass transfer rate. The performance of the electrochemical reactor was investigated by using different porosities. Dimensionless Sherwood and Reynolds numbers were correlated to characterize the mass transport properties of the reactor, and they were fitted to the equation Sh = a.Reb.Sc1/3.

scholarly journals 1RXS J232953.9+062814: A Possible Progenitor of AM CVn Stars

2004 ◽  
Vol 194 ◽  
pp. 109-110
Author(s):  
M. Uemura
Keyword(s):  
Mass Transfer ◽  
Mass Transfer Rate ◽  
Cataclysmic Variables ◽  
High Mass ◽  
Recurrence Time ◽  
Apparent Magnitude ◽  
Evolutionary Status ◽  
Transfer Rates ◽  
Secondary Star ◽  
Orbital Periods

AbstractWe revealed that the hydrogen-rich cataclysmic variable lRXS J232953.9+062814 is an SU UMa-type dwarf nova with a superbump period of 66.774±0.010 min. A photometric orbital period is determined to be 64.184± 0.003 min, which is below the period minimum. Although the standard evolutionary scenario of cataclysmic variables predicts lower mass-transfer rates in systems with shorter orbital periods, its short recurrence time of outbursts and bright apparent magnitude indicate that this object has a relatively high mass-transfer rate. With the analogous system V485 Cen, these objects establish the first subpopulation in hydrogen-rich cataclysmic variables below the period minimum. Concerning the evolutionary status of them, we propose that they are progenitors of AM CVn stars on evolutionary courses in which systems have an evolved secondary star with a hydrogen-exhausted core.

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